Manganosite is a rare manganese oxide that typically occurs as small, emerald green to black crystals or granular masses. It is highly sensitive to atmospheric moisture and oxidation, often altering to hausmannite or pyrolusite when exposed, requiring careful storage for collectors.
Is this manganosite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch manganosite with a known reference. Manganosite sits at Mohs 5-6 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Manganosite leaves a brownish streak.
- 3Read the lusterHold the specimen under a strong light. Manganosite typically shows a submetallic luster.
- 4Match the color rangeCompare against the expected color range: emerald green, grass green, black, brown.
- 5Look at form & habitCrystal system: cubic. Typical habit: massive, granular, or octahedral crystals.
Often confused with
Manganosite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Manganosite leaves brownish, Wüstite leaves black; luster reads submetallic on Manganosite and metallic on Wüstite.
How to tell apart: Streak differs — Manganosite leaves brownish, Periclase leaves white; luster reads submetallic on Manganosite and vitreous on Periclase.
Often found alongside manganosite
Minerals reported to co-occur with manganosite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- MnO
- Mohs hardness
- 5-6
- Density
- 5.18 g/cm³
- Streak
- Brownish
- Luster
- Submetallic
- Transparency
- Opaque
- Crystal system
- Cubic
- Crystal habit
- Massive, Granular, Or Octahedral Crystals
- Cleavage
- Poor
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Metamorphosed Manganese Ore Deposits
- Typical price
- $50-500 depending on specimen quality
Where rockhounds find manganosite
Classic worldwide localities
- Långban, Sweden
- Franklin, New Jersey, USA
- Jacupiranga, Brazil
- Broken Hill, Australia
Field-hunting tip
Look in metamorphosed manganese ore deposits country — that is the host setting where manganosite typically forms. If you start seeing hausmannite, jacobsite, calcite in float, you are in the right ground. Field specimens usually show a massive, granular, or octahedral crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find manganosite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
